1. Field of the Invention
This invention relates to lubricating oils, and particularly to oils suitable for admixing with water to form hydraulic fluids and the like and to aqueous lubricant systems having improved hard water stability characteristics. The invention is even more particularly concerned with fire resistant hydraulic fluids incorporating oil soluble alkylphenoxypolyethoxylated sulfonates as the stability improvers.
2. Discussion of the Prior Art
With the increasing use of hydraulic fluids and similar lubricants, more and more use of oil-in-water emulsion fluids as lubricants in many industrial applications, as for example, hydraulic fluids, is well known. In these fluids, water is the continuous phase and the "oil" is in the dispersed phase. The term oil is not limited in this particular art to its usual meaning but may include non-oil components such as chemical additives to the exclusion of the oil in the dispersed phase.
High content water fluids (HWCF) of the type disclosed herein are usually prepared with various ratios of soft (distilled) water and oil or chemical concentrates. Many of the fluids, however, are unstable if modified, or if unmodified, natural water instead of soft water is used. The stability of HWCF fluids is further affected by the ionic activity of salts present in hard water. Chelating agents have been used in the prior art as one means to overcome this problem. A new emulsifier system has now been developed which makes it possible for high water content fluids to remain stable in the most severe hard water systems.
Propane sulfonates of various amines and polyethoxylated alcohols are known surfactants or surface active agents having a special usefulness in tertiary oil recovery processes. With the increasing use of functional fluids such as hydraulic fluids and more and more sophisticated machine systems that demand closer tolerances to perform new and more difficult functions, there is a critical need for stability improvers for oil-in-water fluids; however, to the best of applicants' knowledge and belief, the HWCF fluid compositions disclosed herein are novel and are heretofore unknown.